There has been known a technique to cover a bottom part of a front portion of a vehicle body using an undercover for the purpose of preventing entry of trash or a rock, for example, into an engine room while a vehicle travels (e.g., see Patent Literature (hereinafter, referred to as “PTL”) 1). The undercover disclosed in PTL 1 includes a stress absorbing portion formed to have a wave-shaped cross-section in order to absorb a collision load in a vehicle collision.